High power energy storage devices, such as supercapacitors and Li-ion batteries, are critical for the development of zero-emission electrical vehicles, large scale smart grid, and energy efficient cargo ships and locomotives. The energy storage characteristics of supercapacitors and Li-ion batteries are mostly determined by the specific capacities of their electrodes, while their power characteristics are influenced by the maximum rate of the ion transport. The talk will focus on the development of nanocomposite electrodes capable to improve both the energy and power storage characteristics of the state of the art devices. Carbon-polymer and carbon-metal oxide nanocomposites have been demonstrated to greatly exceed the specific capacitance of traditional electrodes for supercapacitors. Selected materials showed the unprecedented ultra-fast charging and discharging characteristics. Intelligently designed silicon-carbon-polymer composites showed up to 8 times higher specific capacity than graphite, the conventional anode material in Li-ion batteries, and stable performance for over 1000 cycles. In order to overcome the limitations of traditional composites precise control over the materials’ structure and porosity at the nanoscale was required.